Firmware Update Bandwidth Calculator

Work out firmware update bandwidth instantly with clear inputs, formula shown and shareable results.

About Firmware Update Bandwidth Calculator

Fleet update bandwidth is image size times devices divided by the window, plus about 10% for retries and protocol overhead. Concurrency then sets how long each device has: 5,000 devices in six hours at 50 at a time gives each device just over three minutes.

Formula

OTA bandwidth

bandwidth = image size x devices x overhead x 8 / window seconds; per-device time = window x concurrency / devices

Worked example

With the default values below, Firmware Update Bandwidth Calculator returns Bandwidth required of 1.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Firmware image size: 480 kB
Devices to update: 5,000 devices
Update window: 6 h
Concurrent updates: 50 devices

Results

Bandwidth required: 1.00 Mbit/s
Total data transferred: 2.70 GB
Time per device: 3.60 min
Feasibility: Achievable

Step by step

1Values used
2OTA bandwidth
3Bandwidth required= 1.00 Mbit/s
4Total data transferred= 2.70 GB
5Time per device= 3.60 min
6Feasibility= Achievable

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Should I use delta updates?

Where possible, yes. A binary diff is often 5-20% of a full image, cutting both bandwidth and per-device time by an order of magnitude.

Why limit concurrency at all?

To protect the server and the network, and to keep the blast radius small if the new image proves faulty. Staged rollouts exist for exactly that reason.